PROJECT SUMMARY/ABSTRACT The purpose of this Core is to provide for the consistent preparation of animal models across the various projects. It will be the responsibility of this Core to prepare the chronic animal models for individual investigator use. This will reduce the variability of preparations and will release the individual project directors from the extremely labor intensive task of creating these preparations and providing for their immediate post -operative recovery and care. The Core will also provide echocardiographic data on the animals prior to and during the development of heart failure or sham time controls. The various animal models will be prepared by or under the direction of Dr. Kurtis G. Cornish who has had many years of experience in the preparation of chronic animals and is experienced in these specific animal preparations. He will be assisted by three technicians (including echocardiographic) in the preparation and care of the animals prior to their use by the various investigators. The models prepared by this core will be (1) the coronary ligation model of heart failure (HF) in the rat, (2) the coronary ligation model of HF in the mouse, and (3) the pacing model of HF in the rabbit. Assessment of cardiac function in a serial fashion will be carried out by our ultrasound imaging facility which is part of Core B. We have the capability to carry out echocardiography on conscious rabbits using a Siemans Acuson 512 C echocardiograph and on lightly anesthetized rodents (0.5% isoflourane) using the Visual Sonics VEVO 770. Over the past 5 years we have had a dedicated technician (Ms Johnnie Hackley) carry out these procedures with great efficiency. In addition to the procedures described above the Core is always experimenting with new and novel ways of instrumenting animals and preparing new models. We participate in the training of students and fellows who must to learn these surgical techniques for their projects.